Process for utilizing sapped tanning liquors.



To all whom it may concern:

' NITED STATES r g-un t OFFICE.

' GEORGE iv. cHiLDs, on NEW ORK, N. Y

PROCESS FQB UTILIZING SAPPED TANNING LIQUORS.

Specification of Letters Patent.

Patented March 3, 1908.

Original application filed. May 16, 1906, Serial No. 317,141. Divided and this application filed July ,20, 1906. Serial No. 327,029. I

Be it known that IHGEORGE CHILDs, of New York city, in the county and State of New York, have invented a certain new and useful lm'srovement in Processes for Utilizing Sappe Tanning Liquors, whereof the following is a specification.

This application is a division of my application Serial #317,141, filed May 16, 1906,

which is restricted to a process for treating waste tanning li uors containing mineral acid impurities, as erein contemplated.

It is the object of my invention to utilize the portions of tanning liquors which have become so far sa ped 'i. e. deprived of active tannic material, by contact with hides as to be no'longer available for tanning in' the particular yard in which they have been em to plump the hides; 3O

plo ed. Such sapped liquors being usually pol uted with chemicals introduced thereto or resulting from chemical changes therein, and carrying, a large percentage of nontannic material, are termed runaway or tail liquors and are ordinarily discharged to waste from the last layer in which they have been sappcd. For instance, a ty ical ordinary acid tanning yard 71. e. a yard w iere sulfuric or other mineral acid is employed would comprise five or more layers or vats containing bodies of tanning liquors of difl'ercnt strentlis, the strongest of which would be sup p ied with tanning liquors of approximately 35 degrees barkomcter, which primarily strongest liquor when sapped by the hides would be supplied to the first or other layers of less strength, and thus used until its proportion of tannin 1s so low and its proportion of non-tannic elements (both organic and non-organic) is so high that its use is no longer economical, because of its slow action upon the hides, and it is discharged to waste regardless of its tannin value. Similarly, a typical ordinary non-acid tanning yard '11. e. a yard wherein the hides are plumped without the employment of mineral acid, would comprise a series 'of five or more layers, the strongest of which would receive a tanning liquor of from 16 degrees to 35 degrees barkometcr, which being sapped and transferred to weaker layers or handlers, would be dis chargedto waste from the weakest layer at from 8 degrees to 10 degrees barkometer, then containing a large proportion of nontannic ingredients (both organic and non- .fect such precipitation;

in the last layer organic) and such a small proportion of tannin that its use is no longer economical. Such spent or runaway li uors are impregnated with some or all of t 1e following nontannic ingredients ;lime, lime compounds, volatile and non-volatile acids and organic filth. The presence of an excessive amount of any such impurities always interferes with the action of the tannin on the hides, and particularly when the tanning li nor has been depletedbycontact with the 'ides; so

that although said more or less tannin, for further action containing it mu t be discarded with consequent loss to tie tanner. 'In accordance with my present process, as hereinafter described, suchrunaway or tail li uors may be purified and concentrated to om 1.05 to 1.3 s ecific avity and thereby made avail able or furt er tanning purposes.

The purification above contemplated may spent liquors contain the latter is unavailable be effected as follows :If the spent liquor contains lime or lime compounds these constituents' may be precipitated by the addition of chemicals forming insoluble compounds with l1me.. For instance, ammomum oxalate, sodium phosphate, sodium fluorid,

or carbon dioxid gas may be employed to ef- .The precipitate is then settled out and the supernatent liquor run off for'further purification or concentration. If the liquor contains non-volatile acids, these 'may be either neutralized by the addition of alkali, or the acids maybe precipitated by the addition of bases forming insoluble compounds with the acids. Spent liquors partially purified as aforesaid may then be concentrated to form 1.05 to 1.3 specific gravity for the purpose of removing volatile impurities'and with the effect of reducing the liquors to a form in which the otherwise useless tannin therein becomes available. Of course, such reduction in the bulk of the purified liquors also facilitates their transportation. The otherwise waste liquors thus purified and concentrated may be utilized as follows z-Hides which have been'treated in vats with a tanning solution until they are colored through, are then impregnatedv with a concentrate obtained as above. described. For instance such leather may be placed in a rotarv drum and said con on the hides and the liquor Y Correct H1 in Letters Patent No. 881,094;

' axle or trunnion thereof, and the revolution i of said druin continued until the leather abl sorbs the concentrate which combines with and colors the leather. It may be observed that if said liquors were not concentrated to substantially the consistency described, there would not be sufficient solid residue thereof when the leather is dried, to obtain the result desired. Moreover, if the li uors were concentrated to a reater degree t ey would not be absorbed y the leather; Leather treated as last described may then bebleached, oiled, dried, dampened and rolledin the usual manner,

I do not desire to limit myself to all of the details of procedure above enumerated, as various modifications may be made therein without departing from the essential fea tures of my invention. For instance, some waste liquors will require all of theabove purifying steps, others will require some, and

It is hereby certified that in Letters should read from;

[s aAn] nating leather with 5 uponthe application of George W. Ohilds,

in Processes for Utilizing Sapped Tanning Liquors, an error appears in the printed specification requiring correction, as follows:

. and that the said Letters Patent should be read with this correction.

that'is required to remove volatile matters and make the I claim I V 1. The process which consists in impregconcentrated waste tantannin active and available.

ning liquor.

2. The process. which consists in impreg nat-ing leather with concentrated waste tanning liquor heated above atmospheric temperature, and when the leather is still moist from thetanning process.

In testimony -Whereof', I have hereunto signed my name at New York city. in the county of Ne* Yo1k and State of New York this 18th day of July 1906. I

GEORGE W CHILDS. 1

Witnesses:

VVxG. HoRToN, F. P. PALMER.

Patent No.'881,094, granted March 3, 1908, of New York, N. Y., for an improvement In line 94, page 1, theword form therein that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 24th day of March, 1)., 1908.

C. O. BILLINGS, Acting Commissioner of Patents.

Y Correct H1 in Letters Patent No. 881,094;

' axle or trunnion thereof, and the revolution i of said druin continued until the leather abl sorbs the concentrate which combines with and colors the leather. It may be observed that if said liquors were not concentrated to substantially the consistency described, there would not be sufficient solid residue thereof when the leather is dried, to obtain the result desired. Moreover, if the li uors were concentrated to a reater degree t ey would not be absorbed y the leather; Leather treated as last described may then bebleached, oiled, dried, dampened and rolledin the usual manner,

I do not desire to limit myself to all of the details of procedure above enumerated, as various modifications may be made therein without departing from the essential fea tures of my invention. For instance, some waste liquors will require all of theabove purifying steps, others will require some, and

It is hereby certified that in Letters should read from;

[s aAn] nating leather with 5 uponthe application of George W. Ohilds,

in Processes for Utilizing Sapped Tanning Liquors, an error appears in the printed specification requiring correction, as follows:

. and that the said Letters Patent should be read with this correction.

that'is required to remove volatile matters and make the I claim I V 1. The process which consists in impregconcentrated waste tantannin active and available.

ning liquor.

2. The process. which consists in impreg nat-ing leather with concentrated waste tanning liquor heated above atmospheric temperature, and when the leather is still moist from thetanning process.

In testimony -Whereof', I have hereunto signed my name at New York city. in the county of Ne* Yo1k and State of New York this 18th day of July 1906. I

GEORGE W CHILDS. 1

Witnesses:

VVxG. HoRToN, F. P. PALMER.

Patent No.'881,094, granted March 3, 1908, of New York, N. Y., for an improvement In line 94, page 1, theword form therein that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 24th day of March, 1)., 1908.

C. O. BILLINGS, Acting Commissioner of Patents.

Correch m in Letters Patent No. 881,094.

It is hereby certified that in Letters Patent No. 881,094, granted March 3, 1908, upon the application of George \V. Childs, of New York, N. Y., for an improvenient n Processes for Utilizing Sapped Tanning Liquors, an error appears in the printed :pecification requiring correction, as follows: In line 94, page 1, the word form ehould read from; and thatthe said Letters Patent should be read with this correction herein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 24th day of March, D., 1908.

C. C. BILLINGS,

Acting Commissioner of Patents.

[SEAL] 

